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      1 /*	$NetBSD: _lwp.c,v 1.7 2025/04/25 01:18:38 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Wayne Knowles
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: _lwp.c,v 1.7 2025/04/25 01:18:38 riastradh Exp $");
     35 #endif /* LIBC_SCCS and not lint */
     36 
     37 #include "namespace.h"
     38 
     39 #include <sys/param.h>
     40 #include <sys/types.h>
     41 
     42 #include <machine/frame.h>
     43 
     44 #include <lwp.h>
     45 #include <stdlib.h>
     46 #include <ucontext.h>
     47 
     48 void
     49 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
     50 	void *arg, void *private, caddr_t stack_base, size_t stack_size)
     51 {
     52 	caddr_t sp;
     53 	__greg_t *gr;
     54 	__greg_t *gp;
     55 	__greg_t fp;
     56 
     57 	getcontext(u);
     58 	gr = u->uc_mcontext.__gregs;
     59 	u->uc_link = NULL;
     60 
     61 	u->uc_stack.ss_sp = stack_base;
     62 	u->uc_stack.ss_size = stack_size;
     63 	sp = stack_base + HPPA_FRAME_SIZE;
     64 	sp = (caddr_t)(((uintptr_t)sp + STACK_ALIGNBYTES) & ~STACK_ALIGNBYTES);
     65 
     66 	fp = (__greg_t)start;
     67 	if (fp & 2) {
     68 		gp = (__greg_t *)(fp & ~3);
     69 		fp = gp[0];
     70 		gr[_REG_R19] = gp[1];
     71 	}
     72 	gr[_REG_PCOQH] = fp | HPPA_PC_PRIV_USER;
     73 	gr[_REG_PCOQT] = (fp + 4) | HPPA_PC_PRIV_USER;
     74 	gr[_REG_RP] = (__greg_t) _lwp_exit;
     75 	gr[_REG_ARG0] = (__greg_t) arg;
     76 	gr[_REG_SP] = (__greg_t) sp;
     77 	gr[_REG_CR27] = (__greg_t) private;
     78 }
     79